To explore the efficacy and safety of pembrolizumab in combination with bevacizumab and CapeOX neoadjuvant therapy for the treatment of RAS-mutated, BRAF wild-type, microsatellite-stabilized, locally advanced colorectal cancer. Methods and analysis: A prospective, open-label, single-arm, phase 2 clinical study protocol will enroll a total of 20 patients. The study is designed as a Simon II Optimal study involving 20 locally advanced rectal cancer (LACRC) patients. Initially, 9 patients will be recruited in the Simon I phase, and if more than 1 patient achieves a pathological complete response (pCR), the study will proceed to the II phase. Recruit up to 20 patients in Phase II, and if more than 4 patients achieve pCR, the trial will be considered successful. All enrolled patients will receive 2-4 cycles of neoadjuvant therapy with pembrolizumab + bevacizumab and CapeOX (bevacizumab + oxaliplatin + capecitabine). The primary efficacy endpoint is the pathological complete response (pCR) of the cancer following neoadjuvant therapy. Secondary efficacy endpoints include major pathological response (MPR), objective response rate (ORR), and assessment of adverse events (AEs). Ethics: Ethics approval has been obtained from the Ethics Committee at the First Affliated Hospital (Xijing Hospital)(KY20232402-F-1)
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Pabolizumab is an lgG4 subclass monoclonal antibody humanized against PD-l molecules thatblocks the immune escape mechanism of cancer cells by inhibiting the PD-l receptor oflymphocytes, thereby allowing the immune system to destroy them. In the single-arm study, all enrolled patients received a combination of chemotherapy and immunotherapy, as outlined below: Pembrolizumab: Day 1：Pembrolizumab injection 200mg was administered once and repeated every 21 days, expected to last 2-4 cycles. Two vials (200 mg) of pembrolizumab injection should be diluted into 100-200 mL of saline, and the infusion time should be more than 30 minutes. Chemotherapy (CapeOX regimen): Day 2: Bevacizumab (7.5 mg/kg) + Oxaliplatin (135 mg/m2) + Capecitabine (1 g/m2, did, d1-d14). Treatment repeated every 3 weeks (q3w) until disease progression or intolerable toxicity.
the First Affliated Hospital (Xijing Hospital),the First Affiliated Hospital of Air Force Military Medical University
Xi'an, Shaanxi, China
RECRUITINGPathological complete response rate (pCR)
Pathological complete reand the postoperative pathological findings were statistically completse rate (pCR rate): The pathological status of the primary site was determined in the surgical patient Proportion of patients with complete response:
Time frame: 12 months
Objective response rate (ORR) in the neoadjuvant phase
Obiective response rate (ORR) at the neadjuvant stage: proportion of subjects who achieved partiaand complete response on radiographic assessment (RECIST v1.l) after the end of neoadjuvanttherapy;
Time frame: 36 months
Major pathological response rate (MPR)
Major pathological response rate (MPR rate): The pathological status of the primary site wadetermined in the patients undergoing surgery, and the proportion of patients with residuatumor cells \<10% by pathological detection in postoperative specimens was counted
Time frame: 36 months
Adverse event rate (AE)
Safety: all adverse events, serious adverse events;
Time frame: 36 months
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